Neuroprotection of completely lacerated spinal cord of adult rats by homotopic and heterotopic transplantation

To evaluate the neuroprotective effect of transplants placed in the lesion zone after a complete spinal cord (SC) laceration, two independent series of experiments were carried out. In the first, allogeneic or xenogeneic fetal SC was transplanted into the gaps of the damaged lower thoracic SC of adult rats. In the transplanted rats the incidence of life-threatening complications was reduced, and the survival rate was increased compared with the control group (lesion, without implant). Histological examination showed less damage to the neighboring SC parenchyma in the transplanted rats. The measurement of this neuroprotective effect was made in a second series of experiments. Using the same model of SC injury, allogeneic fetal SC, autologous peripheral nerve and/or adipose tissue were implanted. Rats with implants of Gelfoam and damaged rats without implants were the controls. The implanted rats of all groups, including the Gelfoam group, showed a better survival rate than the nonimplanted rats. Significantly less damage to the neighboring SC parenchyma was measured in implanted rats with any of the live tissues tested compared with non-implanted rats, although no significant differences were observed between the Gelfoam group and the nonimplanted rats. Histological evidence of tissue implant survival was observed in all corresponding groups. It is concluded that the transplanted tissues tested here have a neuroprotective effect, possibly by acting as a buffer to neurotoxic substance(s) released by the stumps, and/or by exerting trophic effect(s) on the host.

Intercalated and paracapsular cell islands of the adult rat amygdala: a combined rapid-Golgi, ultrastructural, and immunohistochemical account

The anterior and rostral paracapsular intercalated islands (AIC and PIC, respectively) were studied in the context of the amygdaloid modulation of fear/anxiety using horizontal sections. The structural analysis carried out using silver-impregnated specimens revealed that the AIC is composed of tightly packed, medium-sized spiny neurons with distinct dendritic and axonal patterns that send projecting axons to the central nucleus of the amygdala. The AIC occupies a strategic position between the basolateral amygdaloid complex and the caudal limb of the anterior commissure from which it receives fibers en passage and axon terminals. Electron microscopic observation of terminal (i.e., synaptic) degeneration 72 h after the surgical interruption of the anterior commissure, confirms the synaptic interaction between the latter and the AIC neurons. These observations suggest that these islands may gate the activity of neurons from the contralateral basal forebrain and synchronize the anxiogenic output of both amygdalae. Immunohistochemical analysis indicated that, within the AIC and rostral PIC, the distance between tyrosine hydroxylase-immunoreactive terminals and the punctate dopamine D(1) receptor immunoreactivity, was in the micrometer range. These results indicate a short distance and a rapid extrasynaptic form of dopamine volume transmission mediated via D(1) receptors in the AIC and PIC which may enhance fear and anxiety by suppressing feed-forward inhibition in the basolateral and central amygdaloid nuclei. The strong suggestion for a commissural axon projection to the AIC documented here, coupled with the previous evidences indicting an isocortical and amygdalar contributions to the anterior commissure, opens the possibility that the AIC may be involved in decoding nerve impulses arising from both the ipsi- and contra-lateral forebrain to, in turn, modulate the homolateral amygdala.

An ectopic adrenocorticotropic hormone syndrome caused by a sacrococcygeal chordoma: report of a case with a slow progression

OBJECTIVE

To report the first case of an ectopic adrenocorticotropic hormone (ACTH) syndrome caused by a sacrococcygeal chordoma.

METHODS

We present a case report with clinical, laboratory, and histologic details.

RESULTS

A 76-year-old man was admitted to the hospital because of urinary obstruction. Five years previously, a urethral mass had been detected, and transurethral prostatectomy had been performed. Annual computed tomographic (CT) scans showed no change in size of the mass. In 1995, skin hyperpigmentation, central obesity, and bilateral edema were noted. The patient was admitted to the hospital in July 1996. A CT scan of the abdomen revealed a large mass close to the sacrum and compressing the bladder and rectum. Cortisol measurements (AM and PM) were 309 and 271 ng/mL, respectively. The plasma ACTH concentration was extremely elevated (3,125 pg/mL). Although resection of the mass was attempted, complete resection was not possible because the tumor had infiltrated the sacrum. Plasma cortisol concentrations in samples obtained 7 and 8 days postoperatively were normal. Plasma ACTH was substantially decreased (180 pg/mL) but remained above normal. The histologic features of the tumor were compatible with a chordoma. Neoplastic cells stained positively for ACTH.

CONCLUSION

This report describes the first case of an ectopic ACTH syndrome caused by a sacrococcygeal chordoma. A slow progression of symptoms in an ectopic ACTH syndrome had been described only for carcinoid tumors. These data add a new entry to the list of neoplasms capable of causing this syndrome.

Different wheat germ agglutinin-horseradish peroxidase labeling in structures related to the development of amygdaline kindling in the rat

The anterior commissure, medial and lateral bed nuclei of the stria terminalis and both sides of the medial prefrontal cortex showed a progressive increasing of wheat germ agglutinin-horseradish peroxidase labeling (WGA-HRP) in successive stages of amygdaline kindling, after 48 h of a right amygdala WGA-HRP injection. In contrast, during the first stages the number of labeled cells in the contralateral amygdala was reduced, reaching control values after the first generalized seizure. The present paper indicates that these structures are involved in the propagation and generalization of the epileptic activity. Our findings show that both sides of the medial prefrontal cortex can be activated before the contralateral amygdaloid complex, during the development of the amygdaline electrical kindling in the rat.

A clinicopathologic variant of intramucosal early gastric cancer with widespread dissemination: report of three cases

We describe the clinicopathological characteristics and postmortem findings of three cases of intramucosal early gastric cancer (EGC) selected from nine cases of our series to characterize its unusual clinical behavior. All patients were treated at the Instituto Nacional de la Nutricion in Mexico City between January 1986 and December 1995. The following features were the most salient of the three cases: (1) The tumors were constituted by only few nests of intramucosal cells; two of them were signet-ring cell carcinomas and the other one was of the intestinal type. (2) Grossly, all tumors were inconspicuous. (3) All the patients had a short clinical course and in none of them the clinical diagnosis was suspected. (4) A wide dissemination was found at autopsy; additionally, in two of the cases, extensive lymphatic and venous thrombi and multiple secondary hemorrhages were found. (5) In all patients, the symptoms and deaths were caused by the metastases. No cases as early as those reported here were found either in the Japanese or in Western literature. Although larger series of EGC should be studied in our country, these findings suggest that at least in Mexico there is a group of EGC with unusual aggressive behavior.

The response of hepatic acute phase proteins during experimental pulmonary tuberculosis

A mouse model of pulmonary tuberculosis induced by the intratracheal instillation of live and virulent mycobacteria strain H37-Rv was used to study the relationship of the histopathological changes with the kinetics of local production and circulating levels of interleukin 6 (IL-6) and the gene expression of acute phase proteins (APP) in the liver. The histopathological studies showed a mononuclear inflammatory infiltrate located in the perivascular, peribronchial, and interstitial areas, with granulomas which started to form 2 weeks after the infection. Numerous IL-6 immunostained activated macrophages were observed in the inflammatory infiltrate, particularly in the interstitial-intralveolar compartment and granulomas, coexisting with a high IL-6 mRNA concentration determined by reverse transcription polimerase chain reaction in lung homogenates, particularly at day 21 of infection. Two peaks of IL-6 demonstrated by ELISA in lung homogenates and sera were observed at day 3 and 21 of infection, being higher on the latter. The hepatic APP mRNA transcription (alpha1-acid glycoprotein, fibrinogen, complement factor 4) analyzed by Northern blot showed a rapid and high increase at day one postinfection, which rapidly decreased and showed another second peak at day 21, when granulomas reached full maturity and the maximal production of IL-6 was observed. At the same time the liver mRNA concentrations of the negative APP albumin showed a substantial decrease. From 1 to 4 months after M. tuberculosis intratracheal instillation, histopathological changes of more severity (pneumonia, necrosis) and chronicity (interstitial fibrosis) were seen, as well as small groups of IL-6 immunostained macrophages in the pneumonic areas, granulomas and perivascular compartments, in coexistence with low IL-6 expression. During this advanced stage of the disease a high mRNA concentration of alpha1-acid glycoprotein and fibrinogen associated with low expression of the albumin gene in the liver continued. Thus, it seems that the time course of hepatic APP genetic expression in experimental pulmonary tuberculosis is related to the production of IL-6 and relevant histopathological changes, particularly the formation of granuloma.

[Giant acinic cell parotid gland adenocarcinoma of the papillary- cystic type]

A case of a 38-year-old male having an acinic cell adenocarcinoma of the parotid gland is reported. The tumor measured 22 cm and histologically it was of the papillary-cystic type. The following features were of interest: 1) the tumor size surpassed the size of previous reported acinic cell adenocarcinomas by 9 cm; and 2) the rarity of its histological variety (cystic papillary) demanded immunohistochemical and electron microscopic studies to confirm the diagnosis.

Perinatal administration of testosterone induces hypertrophy of the anterior commissure in adult male and female rats

A possible sex difference in the mean sagittal area of the anterior commissure (AC) was investigated in normal, newborn-castrated, and perinatally-androgenized rats. A second experiment included castrated adult rats from each sex exposed to testosterone twelve days before sacrifice. In normal rats, as well as in those exposed to testosterone as adults, no quantitative difference was found in the AC. However, perinatal exposure to testosterone induced a 20-25% increase in the mean area of the AC of rats from each sex. It is proposed that gonadal sex steroids may have a reciprocal influence upon the structure of central olfactory pathways, due to the influences of the main olfactory system upon gonadotropin secretion.

Analysis of the local kinetics and localization of interleukin-1 alpha, tumour necrosis factor-alpha and transforming growth factor-beta, during the course of experimental pulmonary tuberculosis

A mouse model of pulmonary tuberculosis induced by the intratracheal instillation of live and virulent mycobacteria strain H37-Rv was used to examine the relationship of the histopathological findings with the local kinetics production and cellular distribution of tumour necrosis factor-alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha) and transforming growth factor-beta (TGF-beta). The histopathological and immunological studies showed two phases of the disease: acute or early and chronic or advanced. The acute phase was characterized by inflammatory infiltrate in the alveolar-capillary interstitium, blood vessels and bronchial wall with formation of granulomas. During this acute phase, which lasted from 1 to 28 days, high percentages of TNF-alpha and IL-1 alpha immunostained activated macrophages were observed principally in the interstium-intralveolar inflammatory infiltrate and in granulomas. Electron microscopy studies of these cells, showed extensive rough endoplasmic reticulum, numerous lysosomes and occasional mycobacteria. Double labelling with colloid gold showed that TNF-alpha and IL-1 alpha were present in the same cells, but were confined to separate vacuoles near the Golgi area, and mixed in larger vacuoles near to cell membrane. The concentration of TNF-alpha and IL-1 alpha as well as their respective mRNAs were elevated in the early phase, particularly at day 3 when the bacillary count decreased. A second peak was seen at days 14 and 21-28 when granulomas appeared and evolved to full maturation. In contrast, TGF-beta production and numbers of immunoreactive cells were low in comparison with the advanced phase of the disease. The chronic phase was characterized by histopathological changes indicative of more severity (i.e. pneumonia, focal necrosis and extensive interstitial fibrosis) with a decrease in the TNF-alpha and IL-1 alpha production that coincided with the highest level of TGF-beta. The bacillary counts were highest as the macrophages became large, vacuolated foamy cells, and containing numerous bacilli with immunoreactivity to mycobacterial lipids and lipoarabinomannan (LAM). These macrophages displayed poor and scarce TNF-alpha and IL-1 alpha immunostaining but still strong immunoreactivity to TGF-beta. These cytokine production kinetics and the spatial relationship between immunostained cells and lung lesions corroborate the important role of TNF-alpha and IL-1 alpha in the constitution of granulomas and immune protection during the early phase of the infection, and also suggest an important if not primary role for TGF-beta in the immunopathogenesis of the advanced forms of pulmonary tuberculosis.

Correlation between the kinetics of Th1, Th2 cells and pathology in a murine model of experimental pulmonary tuberculosis

T-helper 1 (Th1) Th2 kinetics were studied by immunohistochemistry and molecular biology techniques (reverse transcriptase polymerase chain reaction. RT PCR, Southern-blot) during the course of pulmonary tuberculosis induced in BALB/c mice by the intratracheal instillation of the live and virulent strain H-37Rv. The histopathological study clearly showed two phases of the disease. The first one was an acute phase which was characterized by inflammatory infiltrate in the alveolar capillary interstitium, blood vessel and bronchial wall with formation of granulomas. In this acute phase which lasted from 1 to 28 days, a clear predominance of Th1 cells was observed, manifested by a high percentage of interleukin-2 (IL-2) positive cells in the inflammatory infiltrate and granulomas demonstrated by immunohistology, as well as a gradual increment of interferon-gamma (INF-gamma) m-RNA. This was followed by a chronic or advanced phase characterized by pneumonia, focal necrosis and fibrosis, with a Th0 balance due to an equivalent proportion of IL-2 and IL-4 positive cells in the lung lesions, that coincided with the highest level of INF-gamma and IL-4 mRNA. The cytofluorometric analysis of bronchial lavage cells, showed a predominance of CD4 T cells during the acute phase and CD8 T lymphocytes in the chronic phase, gamma-delta T lymphocytes showed two peaks, at the beginning (3 days) and at the end (4 months) of the infection. These results suggest that T-lymphocyte subset kinetics and the pattern of cytokines produced in the lung during tuberculosis infection changed over time and correlate with the type and magnitude of tissue injury.

Urinary angiotensin I-converting enzyme activity is increased in experimental acute renal failure

The angiotensin I-converting enzyme (ACE) activity was studied in 2 experimental models of acute renal failure: (a) rats treated with a single injection of mercuric chloride (1.5 mg/kg) and (b) rats treated with a single injection of potassium dichromate (15 mg/kg). Rats were sacrificed 24 and 48 h after mercuric chloride or potassium dichromate injection. ACE activity was measured in urine, serum, and kidney. These data were compared with vehicle-treated rats. Rats with acute renal failure had proteinuria, polyuria, and decreased creatinine clearance. The damage to the kidney proximal tubule was evident by (a) the histological analysis at light and electron microscopy, (b) the augmentation in the urinary excretion of dipeptidyl aminopeptidase IV and N-acetyl-beta-D-glucosaminidase, and (c) the low molecular weight proteinuria pattern. In addition, the histological analysis at the ultrastructural level showed normal glomeruli appearance. The above data suggest that the increased urinary excretion of enzymes and proteins in rats with acute renal failure is a consequence of tubular injury. Urinary and serum ACE activities increased and kidney ACE activity decreased. Our data suggest that the increase in urine ACE activity may be due to the kidney proximal tubule damage. This work supports the contention that an increase in urine ACE may be an indicator of injury to the proximal tubule.

Histological and subcellular distribution of 65 and 70 kD heat shock proteins in experimental nephrotoxic injury

The cellular distribution of 65 and 70 kD heat shock proteins (HSPs) was studied in the normal rat kidney and after acute tubular necrosis (ATN) induced by inorganic mercury (HgCl2). In the normal kidney the 65 kD HSP was found in the cytoplasm of podocytes and proximal convoluted tubules, whereas the 70 kD HSP was located in nuclei and cytoplasm of podocytes, cortical convoluted, and collecting tubules. The distribution of both HSPs along ATN changed as a function of time. In the early phase, before evidence of histological damage, both HSPs were found in the pielocaly ceal epithelium and medullary collecting tubules. During the necrotic phase, HSPs coexisted with sites of severe damage (i.e. cortical tubules). With immunoelectron microscopy damaged cells showed an abundance of 65 kD HSP-I in mitochondria, as well as in chromatin and nucleoli, while 70 kD HSP-I was overexpressed in the cytoplasm, mito chondria, lysosomes, cytoskeleton, chromatin, and nucleoli, and coincided with urinary excretion of HSPs. In the postregenerative phase, the distribution of HSPs was similar to that found in the normal kidney. HSPs of 65 and 70 kD were encountered constitutionally and their immunolabeling is correlated with the magnitude of cell injury.

Sexually dimorphic contribution from the fornix to the ventromedial hypothalamic nucleus: a quantitative electron microscopic study

Quantitative electron microscopy confirmed that the neuropil of the ventrolateral part of the ventromedial hypothalamic nucleus (VL-VMHN) of the rat is sexually dimorphic with respect to the density of shaft and axo-spinous synapses, both of which are more numerous in the male. In addition, adult rats with complete interruption of the fornix displayed a sexually dimorphic input in the density of fornical synapses in the neuropil of the VL-VMHN, in which degenerating terminals were more numerous in the male. Perinatal exposure of the female to exogenous testosterone or castration of the newborn male 'inverted' these sex differences, demonstrating their hormonal dependence. It is concluded that (1) the fornix provides synaptic input to the VL-VMHN as proven by orthograde degeneration; (2) the number of fornical endings synapsing in the VL-VMHN is greater in the male than in the female; (3) this dimorphism depends of the organizational effect of gonadal sex steroids.

Angiotensin I converting enzyme activity in uranyl nitrate induced acute renal failure in rats

Angiotensin I converting enzyme (ACE) was measured in urine, serum, and tissues from rats with acute renal failure (ARF) induced by a single subcutaneous injection (15 mg/kg BW) of uranyl nitrate (UN). Urine was collected daily until day 5, when rats were sacrificed by decapitation for the obtention of blood serum and tissues. Other groups of rats were sacrificed on days 1 and 2. These rats showed proteinuria and polyuria. The damage to the kidney proximal tubule was shown by (a) histological analysis at light and electron microscopy levels on days 1, 2, and 5, (b) the increase in urinary excretion of dipeptidyl aminopeptidase IV and N-acetyl-beta-D-glucosaminidase on days 1-5, and (c) the low molecular weight proteinuria pattern on day 1. In addition, the histological analysis at the ultrastructural level showed normal glomeruli appearance on days 1 and 2, but structural alterations on day 5. These data suggest that the increased urinary excretion of enzymes and proteins is a consequence of the tubular injury on days 1 and 2, and of tubular and glomerular injury on day 5. ACE activity increased in urine on days 1-5 and in serum on day 5. Tissue ACE activity increased in lung, small intestine, and adrenal glands; and remained unchanged in testis, aorta, brain, kidney, heart, and liver. Our data suggest that: (a) the increase in serum ACE may be secondary to the changes in tissue ACE activity, and (b) the urine ACE increase may be due to the kidney proximal tubule damage. This work supports the contention that an increase in urine ACE may be an indicator of injury to the proximal tubule.

Angiotensin I converting enzyme in glycerol-induced acute renal failure in rats

Angiotensin I converting enzyme (ACE) activity was measured in serum, urine, and tissues of rats with acute renal failure (ARF) induced by glycerol. Glycerol-injected rats were subdivided in three groups according to the urinary volume: oliguric, nonoliguric, and polyuric. The damage to the proximal tubule was evident by (a) the histological analysis at light and electron microscopy level, (b) the augmented urinary excretion of the enzymes dipeptidyl aminopeptidase IV and N-acetyl-beta-D-glucosaminidase, and (c) the low molecular weight proteinuria pattern. On the other hand, the appearance of the glomeruli at the ultrastructural level was normal. These data suggest that the increased urinary excretion of enzymes and proteins in these rats is a consequence of the tubular injury. ARF was markedly higher in the oliguric rats. Urine ACE activity increased in the rats of the three groups, but statistical significance was reached only in the oliguric rats. Serum ACE activity increased in the oliguric rats and tissue ACE activity did not change. It is concluded that the high urinary ACE in glycerol-treated rats is associated with the damage to the kidney tubules. These data support the contention that urinary ACE may be another marker of injury to the proximal tubule.

Effect of dietary antioxidants on puromycin aminonucleoside nephrotic syndrome

Several studies indicate the pathophysiological importance of reactive oxygen species in rats with nephrotic syndrome induced by puromycin aminonucleoside, an experimental model of the human minimal change disease. The role of reactive oxygen species in these rats was further evaluated, examining the effect of dietary deficiency and supplementation of antioxidants (vitamin E and selenium) on biochemical and renal ultrastructural alterations induced by puromycin aminonucleoside. Male Wistar rats, weaned at 3 weeks, were placed on diets normal, deficient or supplemented in vitamin E and selenium for 4 weeks. At the end of this period, rats were divided in two groups: control (sacrificed without any further treatment) and nephrotic (injected with puromycin aminonucleoside and sacrificed 7 and 22 days later). In control rats, the dietary deficiency or supplementation of antioxidants resulted in no significative differences in renal function, proteinuria or kidney ultrastructure. However, kidney lipoperoxidation, kidney glutathione peroxidase activity and circulating levels of vitamin E changed according to the amount of antioxidants in the diet. Seven days after the injection of puromycin aminonucleoside, rats fed normal, deficient or supplemented diets, developed nephrotic syndrome. However, proteinuria, hypoproteinemia, renal dysfunction and ultrastructural alterations were higher in rats fed a deficient diet. In contrast, proteinuria and kidney ultrastructural alterations were lower in rats fed a supplemented diet. Kidney lipoperoxidation and glutathione peroxidase activity increased on day 7 in rats fed a normal or a deficient diet, but not in rats fed a supplemented diet. This study shows that nephrotic syndrome induced by puromycin aminonucleoside in rats is modified by dietary antioxidants (vitamin E and selenium). Dietary supplementation ameliorates it and dietary deficiency exacerbates it.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastrinoma of the common bile duct: immunohistochemical and ultrastructural study of a case

Primary endocrine neoplasms of intra- and extrahepatic biliary ducts are very rare. We describe the first case of a primary endocrine tumor of the common bile duct producing gastrin. A 53-year-old woman had a 3-year history of recurrent duodenal and gastric ulcers as well as obstructive jaundice. A small neoplasm was found in the lower third of the common bile duct, which showed diffuse gastrin production and focal synthesis of serotonin and pancreatic polypeptide by immunohistochemistry and electron microscopy. Although serum gastrin was within normal levels (90 ng/ml), symptoms of peptic acid disease could have been related to hypergastrinemia, since gastric and duodenal ulcers healed after surgical removal of the tumor. She has remained asymptomatic for 8 months.

[Hepatitis C virus infection and membranoproliferative glomerulonephritis]

BACKGROUND AND METHODS

A possible association between hepatitis C virus infection (HCV) and membranoproliferative glomerulonephritis (MPGN) or membranous glomerulonephritis has recently been reported. The pathogenesis of this entity appears to be immunologically mediated. The purpose of this report is to describe the clinical, laboratory, and histopathological features of three patients with chronic HCV infection, without hepatitis B virus disease or autoimmune diseases, but with glomerular disease.

RESULTS

All three patients had chronic hepatopathy stigmata, ascitis, peripheral edema, and normal blood pressure values. Laboratory results showed mild liver function abnormalities and normal levels of blood nitrogenous waste products. Microscopic hematuria, hypoalbuminemia, and variable proteinuria without hypercholesterolemia were found in all cases. All three had positive rheumatoid factor. Only one patient had positive antinuclear antibodies and antimitochondrial antibodies at low levels, and another displayed low C3 and C4 serum levels. Renal histology in the three cases showed type I membranoproliferative glomerulonephritis and hepatic cirrhosis in the liver biopsy.

CONCLUSIONS

This report supports the association between chronic HCV infection and membranoproliferative glomerulonephritis. However, further studies are needed to establish more firmly the association as well as the mechanisms of pathogenesis and causality between them.

[Genetic diversity of 3 DNA probes in the DNA fingerprinting of a Mexican population]

Each individual may be identified by characterizing its genetic material by DNA fingerprinting technology. Its application in Mexico demands a knowledge of the allelic and genotypic diversity of the DNA markers and the probability that two individuals may have the same fingerprint. In the present study the allelic and genotypic diversities of the loci D12S11 (MS43A), D7S22 (g3) and D1S7 (MS1) were determined in 100 Mexican students of the military school of medicine (Escuela Médico Militar de México). The mean allelic frequency of the loci MS43A, g3, and MS1 was 0.01, 0.008 and 0.006, respectively. The heterozygosity of MS43A and g3 was 98 and 99% for MS1. The probability that two individuals might have the same genetic pattern was 2.0 x 10(-4), 1.3 x 10(-4) and 7.2 x 10(-5) for the loci MS43A, g3 and MS1, respectively, and as low as 1.9 x 10(-12) for the three taken together. These data indicate that the genetic diversity of these DNA fingerprinting markers in the Mexican population is high enough to warrant its use in paternity testing and in the identification of individuals in forensic medicine.

Antigenic characterization of Plasmodium vivax with monoclonal antibodies

Monoclonal antibodies were produced against Plasmodium vivax obtained from patients living in southeastern Mexico, where P. vivax malaria is endemic. Nine hybridomas specific for this parasite were obtained. By an indirect immunofluorescence assay, seven antibodies were found to react with epitopes present in the cytoplasm of the infected erythrocyte and two with the parasite itself. By immunoblotting, five monoclonal antibodies reacted with a 17-kD protein band, three with an 85-kD band, and two with one of 45 kD. By immunogold electron microscopy, two antibodies that reacted with the cytoplasm of infected erythrocytes by immunofluorescence also labeled cytoplasmic clefts, and one, in addition, recognized caveola-vesicle complexes and the parasite matrix. These results demonstrate the value of monoclonal antibodies in identifying P. vivax antigens and disclosing their subcellular distribution.

Evidence of a direct projection of the vomeronasal organ to the medial preoptic nucleus and hypothalamus

In rodents the vomeronasal system plays an important role in modulating the hypothalamic control of gonadotropin secretion. It is accepted that the anatomical pathways by which the vomeronasal organ influences the neuroendocrine aspects of the reproductive behavior involves a polysynaptic system, including the accessory olfactory bulb, the 'vomeronasal amygdala', the bed nucleus of the stria terminalis and medial preoptic and ventromedial hypothalamic nuclei. We found that 72 h after unilateral transection of the vomeronasal nerves of an ipsilateral orthograde degeneration is seen in the neuropil of the medial preoptic, ventromedial, and arcuate hypothalamic nuclei. This represents an anatomical evidence of a monosynaptic link between the vomeronasal neuroepithelium and the medial preoptic nucleus, and hypothalamus.

Evidence that human placenta is a site of sex hormone-binding globulin gene expression

The presence of an androgen-binding component in placenta was investigated in vitro using a tissue culture system of human placental explants. Explants of trophoblastic tissue from normal term placentas were kept in culture under appropriate conditions for at least 48 h in a serum-free medium. The existence of an androgen-binding protein was explored by binding assays, immunohistochemistry studies and Northern blot analyses of placental mRNA. Steady-state polyacrylamide gel electrophoresis and Scatchard plot analyses revealed the presence of a high affinity specific binding component for 5 alpha-dihydrotestosterone in cultured placenta. Immunohistochemical studies performed on intact placenta and on Percoll-gradient purified trophoblastic cells demonstrated the presence of specific immunoreactivity in the cytoplasm of syncytial cells. Northern blot analyses of placental mRNA showed a single hybridizable 32P-labeled human sex hormone-binding globulin (SHBG) cDNA band of approx. 1.6 kb which was identical in size to that obtained with liver mRNA. The results strongly suggest the placenta as an origin of SHBG and point out this tissue as an additional site of SHBG synthesis during pregnancy.

Diffuse lymphoplasmacytic infiltration of the small intestine with damage to nerve plexus. A cause of intestinal pseudo-obstruction

We describe the clinicopathologic characteristics of three patients with chronic intestinal pseudo-obstruction and malabsorption. The patients were young women (average age, 25 years) who presented with abdominal pain, nausea, vomiting, diarrhea, and weight loss that led to extreme inanition and death in two patients despite multiple treatment schemes. The evolution of the process averaged 8 years. No case manifested evidence of malignant lymphoproliferative progression. Histologically, a diffuse lymphoplasmacytic infiltrate that affected all the layers of the intestinal wall was observed in full-thickness biopsy specimens. The proliferating lymphocytes were small and mixed with mature plasma cells that proved to be polyclonal on immunohistochemical analysis. An outstanding finding in all three cases was extensive damage to submucosal and myenteric nerve plexus associated with a lymphoid infiltrate. Quantification of the myenteric plexus by using immunohistochemical and morphometric techniques also revealed a marked reduction in their number. We concluded that diffuse lymphoplasmacytic infiltration of the small intestine associated with damage to the intestinal nerve plexus constitutes a specific disorder that is different from other diseases that produce intestinal pseudo-obstruction.

Ultrastructural and immunocytochemical study of a primary gastrinoma of the liver

A primary hepatic gastrinoma found in a 13-year-old boy was studied by light microscopy, immunohistochemistry, electron microscopy, and immunoelectron microscopy. Results were consistent with a neuroendocrine neoplasm with abundant gastrin-immunoreactive cells. Unlike all previously reported cases of primary hepatic neuroendocrine tumors, which have been endocrinologically asymptomatic, the patient had a Zollinger-Ellison syndrome apparently cured by surgical resection of the tumor.

Rapeseed diet and hepatocyte hypertrophy: an experimental morphometric study

A previous study suggested that a rapeseed diet induced hepatocellular hypertrophy in normal albino rats. In the present study morphometry confirmed that a rapeseed diet produces hepatocytic hypertrophy which, according to cytological findings, is primarily due to an increase in the cytoplasmic area. A combination of a rapeseed diet and the administration of carbon tetrachloride (CCl4) also led to hepatocellular hypertrophy but the histological picture of the cirrhosis was similar to the one in control animals receiving CCl4 alone. The fact that the hypertrophy was primarily due to organelles supports the idea that a component or components of the rapeseed may modify protein turnover in the parenchyma of the liver.

Ultrastructural evidence of a sexual dimorphism in the neuropil of the medial preoptic nucleus of the rat: a quantitative study

In the rat, a new structural sex difference of the nervous system was found: the density of axodendritic synapses (ADS) is larger in the male central component of the medial preoptic nucleus (MPNc), as proven by quantitative electron microscopy. The study included 24 animals divided into four groups (n = 6): control males (CM), control females (CF), males castrated as newborn (MGx) and males castrated as newborn and treated 10 days with daily injections of testosterone. No significant differences were found in the number of axospinous synapses among all groups; however, the number of ADS was significantly larger in CM when compared to that of the CF. This difference was abrogated by castration of the newborn male and restored by perinatal treatment with testosterone. Further, no difference in ADS was encountered between CF and MGx. The present data, together with previous studies which indicate that sex steroids do modify the number of synapses in other nuclei of the brain, led us to conclude that the sex difference in the number of ADS within the MPNc is determined by the organizational effect(s) of testosterone.

Primary carcinoid of the common bile duct. Immunohistochemical characterization of a case and review of the literature

A 39-year-old woman with a primary carcinoid of the common bile duct is presented. The tumor showed argyrophilia; and, by immunohistochemical studies, chromogranin, serotonin, and somatostatin were demonstrated. The patient has no symptoms 42 months after surgical treatment. To the authors' knowledge, this is the first report of a carcinoid of the common bile duct as studied by immunohistochemistry. When six choledochal carcinoids were reviewed, the following characteristics were observed: in none of the cases were endocrine symptoms present; women were affected more frequently than men; the carcinoids occurred in younger patients than did adenocarcinomas; metastases were present in half of the patients; and, as a group, carcinoids seemed to have a better prognosis than adenocarcinomas in this location.

Immunohistochemical demonstration of androgen-binding protein in the rat prostatic gland

Androgen-binding protein (ABP) is one of the best-characterized products of synthesis by the Sertoli cells in the rat. Although the exact physiological role of ABP remains to be determined, it has been widely used to study Sertoli cells and testicular function in this species. Since this protein is the principal carrier for testosterone in rat testis and epididymis, we decided to investigate ABP immunoreactivity (ABP-I) in androgen-dependent organs, including testicle, epididymides, prostate, and seminal vesicles. The location of ABP was investigated by immunohistochemistry using specific antisera against rat ABP. As previously described in the testis, rat ABP-I was identified in the seminiferous tubules within the cytoplasm of the Sertoli cells and the tubular luminae. The epididymis showed ABP-I only in epithelial cells of the proximal caput. We demonstrated ABP-I in the apical portions of epithelial cells of the rat prostate. Short-term castration and/or ligation of the efferent ducts did not suppress prostatic ABP-I. ABP-I was not present in seminal vesicles of control rats nor under any of the experimental conditions used throughout this study. The results also indicate the presence of ABP-I in prostatic epithelium, probably because of a mechanism similar to that described in epididymis. Our data support and enhance the concept that ABP may serve as a transmembrane carrier protein for androgens in androgen target organs in the male reproductive tract.

The role of the endoscopic biopsy in the diagnosis of gastric lymphoma: a morphologic and immunohistochemical reappraisal

Forty-three endoscopic biopsies from 29 patients with confirmed gastric lymphoma (GL) were analyzed retrospectively to establish the morphologic criteria of greatest diagnostic significance. An average of 10 tissue samples was obtained at each endoscopy. In 44% of the cases, lymphoma was discovered in only one or two of the tissue portions. Eighteen lymphomas were primary, six were probably primary, and five were generalized. The diagnosis of lymphoma was originally suspected or established in 46% of the biopsies. However, a review of the histologic sections indicated that the changes, either diagnostic of or compatible with lymphoma, were present in 75% and 18% of the sections, respectively. Most diagnostic errors consisted of confusion with diffuse lymphoid infiltrates in chronic gastritis and/or peptic ulcer, and less frequently with poorly differentiated carcinoma. In those cases confused with chronic gastritis or peptic ulcer, biopsies showed centrocyte-like cells of the standard type or small lymphocytes which produced: (1) a marked increase in density of the lymphoid infiltrate in the gastric mucosa, (2) massive substitution of gastric glands by lymphoid infiltration, and (3) a collection of lymphocytes infiltrating and partially destroying isolated glands (lymphoepithelial lesion). From 48 biopsies having intense benign lymphoid infiltrates, three were interpreted (by means of a blinded study) as compatible with GL. In poorly differentiated neoplasms (blastic and pleomorphic types), cytologic features were sufficient to diagnose GL or malignant neoplasms; immunohistochemical techniques were useful to define their lymphoid nature. It is concluded that many GLs can be suspected or correctly diagnosed by routine endoscopic biopsy.

Neuroendocrine carcinoma of the ampulla of vater. A case of absence of somatostatin in a vasoactive intestinal polypeptide-, bombesin-, and cholecystokinin-producing tumor

A 31-year-old patient with a clinical picture of obstructive jaundice had surgical treatment, and a primary carcinoid of the ampulla of Vater (VA) was found. The tumor was studied with light microscopy, immunohistochemistry, and electron microscopy. The neoplasm had histopathologic and cytopathologic features similar to those encountered in typical neuroendocrine neoplasms. It is interesting that immunohistochemical techniques disclosed the presence of vasointestinal polypeptide, cholecystokinin, and bombesin; however, unlike most neuroendocrine neoplasms arising in VA, no somatostatin-immunoreactive cells were found.

Effects of electromagnetic extracorporeal shock wave lithotripsy on the fine structure of the liver and gallbladder of the rabbit

The fine structure of the liver and gallbladder of rabbits submitted to lithotripsy was studied with transmission electron microscopy. Alterations found in both organs involved capilaries, venules and small veins as well as neighboring tissues. In the liver the most important alterations were seen in those areas located about central veins. These consisted in mitochondrial vacuolation, increase in the cytoplasmic electrondensity, and necrosis. In the gallbladder different stages of epithelial damage and regeneration (i.e. mitoses) were observed. Vascular damage was characterized by mitochondrial swollen and increase of nuclear and cytoplasmic electrondensities. The gallbladder's stroma displayed cell vacuolation, pyknosis, and edema. It is proposed that the damage produced by lithotripsy results from a direct colision of red blood cells upon blood vessels. Tissue damage was considered focal and in most cases reversible.

Primary recurrent leiomyosarcoma of the breast. Case report with ultrastructural and immunohistochemical study and review of the literature

The authors report a case of recurrent mammary leiomyosarcoma in a 50-year-old woman. The neoplasia, with a recognized clinical evolution of 11 years, was resected on two occasions and had not metastasized. Microscopic examination showed 4 mitoses/10 high-power fields, moderate cytologic atypia, and, ultrastructurally, abundant myofibrils with condensations. Immunoperoxidase stains had positive results for muscle-specific antigen and showed focal reactivity for epithelial membrane antigen and S-100 protein. Analysis of the ten cases (including the present one) reveals that this neoplasm has appeared with greater frequency in women with an average age of 52 years. All neoplasms have been limited to the breast at the time of diagnosis. As a group, they have better prognosis than other sarcomas of the breast, although the possibilities of recurrence or dissemination exist, even many years after the primary extirpation. The size of the tumor and mitotic activity seem to be of little prognostic value. Mammary leiomyosarcoma shares clinical and pathologic similarities with subcutaneous leiomyosarcoma in other anatomic sites.

Cholecystokinin synapses in the sexually dimorphic central part of the medial preoptic nucleus

The distribution of immunoreactive cholecystokinin synapses in the medial preoptic nucleus was studied. At the light microscopic level, the relative density of cholecystokinin in the nucleus corresponds to its three subdivisions. The sexually dimorphic central part of the nucleus was filled with a very dense plexus of cholecystokinin fibers/terminals. At the ultrastructural level, cholecystokinin-positive boutons contained labeled, dense core vesicles and clear vesicles as well as a population of unlabeled vesicles. The cholecystokinin boutons formed axodendritic, axosomatic, and axoaxonic interactions. Very few of the boutons were found in apposition with unlabeled elements but without any evidence of contact, i.e., synaptoid-type. Interestingly, cholecystokinin-positive, dendrite-like structures occasionally extended thin processes that were observed to end in a bouton containing both light and dense core vesicles. These varicosities were observed to have synaptoid endings. The dense innervation and synaptoid interaction of cholecystokinin elements in the central part of the medial preoptic nucleus may help to clarify the peptide's function in the medial preoptic area.